Here is the full list of all 28 Quest Of Graal achievements.
Complete 100% of the game
Unlock a character
Unlock all characters
Find your first Graal
Find 10 Graals
Find all the Graals
Finish Camelot
Finish Brocelia
Finish Lake
Finish Avalon
Finish Warp
Finish all worlds
Find your first card
Find 10 cards
Find all cards
Unlock Lopside
Defeat your first ghost
Defeat 10 ghosts
Defeat all ghosts
Have your first duel
Complete the tutorial
Defeat 250 monsters
Destroy 25 vehicles
100 deaths
Defeat 500 monsters
Defeat 1000 monsters
Finish Plain
Unlock a guest